Why e and the natural logarithm, rather than other bases, are used in so many situations

Atotal of 766 tickets were sold for the school play. they were either adult tickets or student tickets. there were 66 more student tickets sold than adult tickets. how many adult tickets were sold?

What is the measure of angle 1? a.28 b.152 c.168 d.64

Which of the following is the maximum value of the equation y=-x^2+2x+5 a. 5 b. 6 c. 2. d. 1